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…cument) Comprehensive coverage of how non-plain-text files work: - File Formats: magic bytes, headers/trailers, hex walkthroughs, endianness - Image Formats: JPEG DCT pipeline, PNG chunks, GIF, WebP, AVIF internals - File Metadata: EXIF structure, GPS coordinates, XMP, ID3, privacy implications - Audio and Video Formats: codecs vs containers, MP3 frames, MP4 boxes, streaming - Archive and Compression: ZIP central directory, TAR headers, LZ77/DEFLATE, zstd - Document Formats: PDF object graph, DOCX/XLSX ZIP structure, EPUB internals https://claude.ai/code/session_01Q7ZjU9KDPBgT8yWJyA9GXq
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Summary
This PR adds a comprehensive suite of documentation covering file formats, metadata standards, and media encoding across the Computer Science knowledge base. Seven new concept documents have been created to provide deep technical coverage of how digital data is structured and stored.
Key Changes
File Formats — Foundational document covering binary file anatomy, magic bytes, format categories (text, binary, containers), and endianness. Serves as the entry point for format-specific documentation.
File Metadata — Extensive coverage of EXIF (with IFD structure and GPS data), XMP (XML-based metadata), ID3 tags (MP3 metadata), and video metadata standards. Includes privacy implications and practical tools (exiftool).
Image Formats — Deep technical dives into JPEG (DCT compression pipeline, quantization, artifacts), PNG (filtering, chunk structure, color types), GIF, WebP, AVIF, and other image formats with hex walkthroughs and compression comparisons.
Document Formats — Coverage of PDF (object graph model, content streams, incremental updates), Office Open XML (DOCX/XLSX structure as ZIP archives), OpenDocument Format, EPUB (web standards approach), and RTF.
Archive and Compression Formats — Comparison of compression algorithms (DEFLATE, LZ77, Zstandard, Brotli, LZMA), archive formats (TAR, ZIP), and ZIP internals including the central directory structure.
Audio and Video Formats — Distinction between codecs and containers, video codec comparison (H.264, H.265, AV1, VP9), audio codec details (MP3 frame structure, psychoacoustic modeling), and container formats (MP4, MKV, WebM, OGG).
Image Formats — Companion document with detailed coverage of PNG chunk structure, JPEG binary format, GIF animation, WebP, AVIF, HEIF, and format selection guidance.
Notable Implementation Details
Hex walkthroughs — Multiple documents include byte-level breakdowns of file structures (PNG signature, JPEG markers, ZIP central directory, MP3 frames) to aid understanding of binary formats.
Practical examples — Command-line examples for viewing/stripping metadata (exiftool), compression (zstd, brotli), and archive inspection (unzip).
Comparative tables — Consistent use of format comparison tables showing compression ratios, speed, licensing, and typical use cases.
Privacy focus — File Metadata document emphasizes GPS data leakage and platform-specific metadata stripping behavior.
Cross-references — Documents link to related concepts (Character Encoding, Serialization, Database Engines) and are indexed in the Computer Science and Tools MOCs.
All documents are marked as complete, fundamentals-level difficulty, and tagged appropriately for discoverability.
https://claude.ai/code/session_01Q7ZjU9KDPBgT8yWJyA9GXq